package cn.lr.demo;

import java.util.Stack;

/**
 * 二叉树的链式存储
 */
public class BinaryTree {

	
	private TreeNode root=null;
	
	public BinaryTree(){
		root=new TreeNode(1,"rootNode(A)");
	}
	
	/**
	 * 创建一棵二叉树
	 * <pre>
	 *           A
	 *     B          C
	 *  D     E            F
	 *  </pre>
	 * @param root
	 */
	public void createBinTree(TreeNode root){
		TreeNode newNodeB = new TreeNode(2,"B");
        TreeNode newNodeC = new TreeNode(3,"C");
        TreeNode newNodeD = new TreeNode(4,"D");
        TreeNode newNodeE = new TreeNode(5,"E");
        TreeNode newNodeF = new TreeNode(6,"F");
        root.leftChild=newNodeB;
        root.rightChild=newNodeC;
        root.leftChild.leftChild=newNodeD;
        root.leftChild.rightChild=newNodeE;
        root.rightChild.rightChild=newNodeF;
	}
	
	
	public boolean isEmpty(){
		return root==null;
	}

	//树的高度
	public int height(){
		return height(root);
	}
	
	//节点个数
	public int size(){
		return size(root);
	}
	
	
	private int height(TreeNode subTree){
		if(subTree==null)
			return 0;//递归结束：空树高度为0
		else{
			int i=height(subTree.leftChild);
			int j=height(subTree.rightChild);
			return (i<j)?(j+1):(i+1);
		}
	}
	
	private int size(TreeNode subTree){
		if(subTree==null){
			return 0;
		}else{
			return 1+size(subTree.leftChild)
					+size(subTree.rightChild);
		}
	}
	
	//返回双亲结点
	public TreeNode parent(TreeNode element){
		return (root==null|| root==element)?null:parent(root, element);
	}
	
	public TreeNode parent(TreeNode subTree,TreeNode element){
		if(subTree==null)
			return null;
		if(subTree.leftChild==element||subTree.rightChild==element)
			//返回父结点地址
			return subTree;
		TreeNode p;
		//现在左子树中找，如果左子树中没有找到，才到右子树去找
		if((p=parent(subTree.leftChild, element))!=null)
			//递归在左子树中搜索
			return p;
		else
			//递归在右子树中搜索
			return parent(subTree.rightChild, element);
	}
	
	public TreeNode getLeftChildNode(TreeNode element){
		return (element!=null)?element.leftChild:null;
	}
	
	public TreeNode getRightChildNode(TreeNode element){
		return (element!=null)?element.rightChild:null;
	}
	
	public TreeNode getRoot(){
		return root;
	}
	
	//在释放某个结点时，该结点的左右子树都已经释放，
	//所以应该采用后续遍历，当访问某个结点时将该结点的存储空间释放
	public void destroy(TreeNode subTree){
		//删除根为subTree的子树
		if(subTree!=null){
			//删除左子树
			destroy(subTree.leftChild);
			//删除右子树
			destroy(subTree.rightChild);
			//删除根结点
			subTree=null;
		}
	}
	
	public void traverse(TreeNode subTree){
		System.out.println("key:"+subTree.key+"--name:"+subTree.data);;
		traverse(subTree.leftChild);
		traverse(subTree.rightChild);
	}
	
	//前序遍历
	public void preOrder(TreeNode subTree){
		if(subTree!=null){
			visted(subTree);
			preOrder(subTree.leftChild);
			preOrder(subTree.rightChild);
		}
	}
	
	//中序遍历
	public void inOrder(TreeNode subTree){
		if(subTree!=null){
			inOrder(subTree.leftChild);
			visted(subTree);
			inOrder(subTree.rightChild);
		}
	}
	
	//后续遍历
	public void postOrder(TreeNode subTree) {
		if (subTree != null) {
			postOrder(subTree.leftChild);
            postOrder(subTree.rightChild);
            visted(subTree);
        }
	}
	
	//前序遍历的非递归实现
	public void nonRecPreOrder(TreeNode p){
		Stack<TreeNode> stack=new Stack<TreeNode>();
		TreeNode node=p;
		while(node!=null||stack.size()>0){
			while(node!=null){
				visted(node);
				stack.push(node);
				node=node.leftChild;
			}
			while(stack.size()>0){
				node=stack.pop();
				node=node.rightChild;
			} 
		}
	}
	
	//中序遍历的非递归实现
	public void nonRecInOrder(TreeNode p){
		Stack<TreeNode> stack =new Stack<BinaryTree.TreeNode>();
		TreeNode node =p;
		while(node!=null||stack.size()>0){
			//存在左子树
			while(node!=null){
				stack.push(node);
				node=node.leftChild;
			}
			//栈非空
			if(stack.size()>0){
				node=stack.pop();
				visted(node);
				node=node.rightChild;
			}
		}
	}
	
	//后序遍历的非递归实现
	public void noRecPostOrder(TreeNode p){
		Stack<TreeNode> stack=new Stack<BinaryTree.TreeNode>();
		TreeNode node =p;
		while(p!=null){
			//左子树入栈
			for(;p.leftChild!=null;p=p.leftChild){
				stack.push(p);
			}
			//当前结点无右子树或右子树已经输出
			while(p!=null&&(p.rightChild==null||p.rightChild==node)){
				visted(p);
				//纪录上一个已输出结点
				node =p;
				if(stack.empty())
					return;
				p=stack.pop();
			}
			//处理右子树
			stack.push(p);
			p=p.rightChild;
		}
	}
	public void visted(TreeNode subTree){
		subTree.isVisted=true;
		System.out.println("key:"+subTree.key+"--name:"+subTree.data);;
	}
	
	
	/**
	 * 二叉树的节点数据结构
	 */
	private class  TreeNode{
		private int key=0;
		private String data=null;
		private boolean isVisted=false;
		private TreeNode leftChild=null;
		private TreeNode rightChild=null;
		
		public TreeNode(){}
		
		/**
		 * @param key  层序编码
		 * @param data 数据域
		 */
		public TreeNode(int key,String data){
			this.key=key;
			this.data=data;
			this.leftChild=null;
			this.rightChild=null;
		}


	}
	
	
	//测试
	public static void main(String[] args) {
        BinaryTree bt = new BinaryTree();
        bt.createBinTree(bt.root);
        System.out.println("the size of the tree is " + bt.size());
        System.out.println("the height of the tree is " + bt.height());
        
        System.out.println("*******(前序遍历)[ABDECF]遍历*****************");
        bt.preOrder(bt.root);
        
        System.out.println("*******(中序遍历)[DBEACF]遍历*****************");
        bt.inOrder(bt.root);
       
        System.out.println("*******(后序遍历)[DEBFCA]遍历*****************");
        bt.postOrder(bt.root);
        
        System.out.println("***非递归实现****(前序遍历)[ABDECF]遍历*****************");
        bt.nonRecPreOrder(bt.root);
        
        System.out.println("***非递归实现****(中序遍历)[DBEACF]遍历*****************");
        bt.nonRecInOrder(bt.root);
        
        System.out.println("***非递归实现****(后序遍历)[DEBFCA]遍历*****************");
        bt.noRecPostOrder(bt.root);
    }
}
